How to tackle the most common aquaculture challenges

The unpredictable nature of the current environment — including the increasing prices of raw materials for aquaculture, the reduced availability of animal-based proteins, using fish meal for fish feed, disease risks and health pandemics — is an ongoing concern, and the industry will be impacted by all of these issues for years to come. It is time for us all, as an industry, to adopt new strategies and learn to co-exist with new norms. This will, no doubt, be a test for each stage of the food chain, but there are some long-term approaches that the industry can take to help increase our profitability and sustainability.  

The ultimate objective for producers

Without a doubt, the most important goals for producers in the aquaculture industry are to:

• Produce healthy fish in the most sustainable manner.
• Reduce the use of marine ingredients.
• Aim for increased growth.
• Reduce operational costs.

Attempting to improve weight gain and lower the feed conversion ratio (FCR) puts increased pressure on the digestive tract to function with the highest efficiency. Considering this, maintaining the health and welfare of fish and shrimp will still be critical for efficient production. Stress from the rigors of production, disease resistance, age and feed, combined with external factors — such as temperature, salinity and pH — can cause imbalances in the gut, potentially leading to disease.

Diets in the aquaculture industry have changed significantly over the last number of years and will continue to be modified and improved. From a sustainability perspective, there is an ever-growing need to reduce fish meal and fish oil in aquaculture feeds. Feed ultimately provides energy and nutrients to support the development of the species. Providing the correct balance of feed is crucial for protecting against foreign pathogens and is critical for the system to function optimally. Formulations must be highly digestible, and each ingredient must add value to and enrich the diet to impact performance. As feed ingredients are derived from several different sources, significant planning, research and development can lead to more sustainable, economical and responsible feed solutions. When considering any change to an existing diet, the nutritional requirements of the species must be met. Each aquatic species has a different set of nutritional requirements, and they can fluctuate depending on their stage in the lifecycle.

Aquafeed is comprised of a selection of natural feed ingredients, including:

• Essential amino acid sources
• Essential fatty acids
• Vitamins and minerals

Imbalances in the diet will lead to a lack of required nutrients, which will have a direct impact on the performance and welfare of farmed fish.

The gut is the key to success

To fully protect fish and shrimp for long-term success, protecting them right from the start is crucial. Their first point of interaction with outside world — the skin, gut and gills — play a vital role in protecting the animal against the environment and its internal physiology. The gut is a complex system of tissues and organs that play an essential role in all interactions related to these functions:

• Food digestion and absorption
• Metabolism
• Defense mechanisms
• Immune response

An unhealthy gut cannot defend itself. A healthy gut, on the other hand, can digest and absorb the maximum amount of nutrients, providing the most benefit for the farmer. 

Importance of maintaining and improving gut integrity

1. Choose the correct selection of ingredients to prevent gut inflammation.
2. Increase the growth of good bacteria.
3. Create a solid foundation for health and growth.

The use of mannan-oligosaccharides (MOS) in diets has been shown to improve gut performance. However, their function can be altered depending on the strain of yeast, the fermentation conditions and the processing methods.

Recent trials carried out with trout, carp, catfish, tilapia, seabass, sea bream, sole and salmon show the effectiveness of MOS in aquaculture species, promoting a healthy growth rate and improving intestinal morphology. The effects of different concentrations of dietary MOS in carp (Cyprinus carpio) included higher weight gains as well as improved FCR, productivity and immune parameters (Zhou and Li, 2004). Improvements in growth performance and reduced FCR and mortality have also been observed in MOS-treated juvenile common carp (Culjak et al., 2006) and rainbow trout (Staykov, 2007). Similar results have also been observed in European seabass (Torrecillas et al., 2006; Ramirez et al., 2016).

Bio-Mos® is a unique product derived from a selected strain of Saccharomyces cerevisiae yeast using a proprietary process developed by Alltech, Bio-Mos is incorporated into animal diets to support overall animal performance. Effective during all phases of growth, Bio-Mos is designed to feed the gastrointestinal tract, thereby maximizing performance and profitability. Bio-Mos has been shown to maintain gastrointestinal health and integrity, contributing to increased growth and lower FCR. It has also displayed an ability to increase the absorptive surface area supporting the immune system, and  stimulating the natural defenses and health status of the animal.

The inclusion of Bio-Mos in the diet improves gut morphology by increasing the microvilli density and length, leading to an enhanced absorptive surface. A report completed by Dimitroglou et al. (2007) demonstrated the effects on the gut morphology of several species. Similarly, in European seabass, an increased number of folds was noted, indicating a larger surface area for nutrient management (Torrecillas et al., 2015).

More and more fish farmers around the world are finding that including Bio-Mos and Actigen in their strategic feeding programs provides a successful and cost-effective solution to their animal health problems. Getting this aspect right as early as possible in the production cycle will ultimately benefit fish performance in later life.

Reducing costs will always be an important element in the viability of any farmed species; however, it is clear that the positive impact of solid gut health will affect production and performance and help mitigate the challenges faced by farmers worldwide. Providing fish with quality nutrients, backed by innovative technological solutions based on sound research and development, plays an important role in ensuring financial success.

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